This application is a divisional application of U.S. patent application Ser. No. 10/339,191 which was filed on Jan. 9, 2003 and is still pending.
The present invention relates to vacuum cleaners. More specifically, the invention relates to self-propelled vacuum cleaners.
Known self-propelled vacuum cleaners include an electric motor disposed in a nozzle base of the cleaner for driving a set of driven wheels. The drive motor, via a clutch, exerts a driving force on the driven wheels in the direction of movement desired by the operator. Some operators value self-propelled vacuum cleaners because they are easier to move from place to place while vacuuming a room.
In the prior art self-propelled vacuum cleaners, a clutch mechanism is provided to allow the motor, which normally rotates only in a single direction, to drive the vacuum cleaner in both a forward and a reversed direction. It is apparent that clutches add to the complexity of the vacuum cleaner power drive system. Accordingly, it would be desirable to have a clutchless direct drive type vacuum cleaner.
As is well known, vacuum cleaners also include height adjustment mechanisms to enable the vacuum cleaner to be employed on carpeting of various heights or on bare floors. Conventionally, the nozzle base had to include both drive wheels for the power drive mechanism and separate rollers or wheels which were coupled to the nozzle height adjustment mechanism of the vacuum cleaner. Accordingly, it would be desirable to provide a drive mechanism which can also serve as part of a height adjustment mechanism for the vacuum cleaner in order to reduce the number of parts in the nozzle base, thereby reducing both the complexity and the cost of manufacture of the nozzle base.